A specular map is a texture used in 3D graphics to define how shiny or reflective a surface appears. It controls the intensity of specular highlights, which are bright spots that appear on shiny surfaces when light hits them. The map typically uses grayscale values, where white indicates high reflectivity and black indicates no reflectivity. In computer graphics, specular maps are often used alongside other maps, such as diffuse maps and normal maps, to create realistic materials. By adjusting the specular map, artists can simulate various surfaces, from shiny metals to dull fabrics, enhancing the overall visual quality of 3D models.